This^^^ a homeowner doesn't need a pro 4-5 cube saw, period. Will it be faster in big wood? of course it will, so what. Buy the saw which meets to the cutting conditions you will see the most often. MS260 or 50cc saws are awesome in MOST situations you will encounter, [occasional brush clearing, firewood chores, falling the occasional tree to 20inch DBH]
We do pre-commercial thinning/timber-stand improvement where we literally fall hundreds of 6-12 inch diameter DBH trees per man day. The fastest combo we have found is a 50cc saw and a razor sharp .325 chain. A bigger saw slows you down do to weight/bulk, a smaller saw has negligible weight savings and is underpowered.